Timepiece-regulator machine



1967 w. F. FITZGERALD 3,334,512

TIMEPIECE-REGULATCR MACHINE Filed Jan. 14, 1965 3 Sheets-Sheet 1 OSCILLATOR 20 ADJUSTER MON I TOR MID/CA TOR m PULSE TIMER SENSOR AMPLIFIER co/v T901.

19 7 6 IL gzgxgg F CUTTING TIME CIRCUIT TRIGGER 9 INVENTOR WILL IA'M F. FITZGERAL D Aug. 8 1967 w. F. FITZGERALD 3,334,512

TIMEPIECE-REGULATC'R MACHINE Filed Jan. 14, 1965 3 Sheets-Sheet 2 HA IRSPRING CU T Q56? ULA TIES (:3 m WWW) WILLIAM F. FITZGERALD Aug. 8, 1967 W. F. FITZGERALD TIMEPIECE-REGULATOR MACHINE Filed Jan. 14, 1965 5 Sheets-Sheet 5 INPUT our ur INPUT ourpur o Alum,

INVENTOR. WILLIAM F. FITZGERALD A 1 Tom! Ys.

United States Patent 3,334,512 TIMEPIECE-REGULATOR MACHINE William F. Fitzgerald, North Little Rock, Ark., assignor to The United States Time Corporation, Waterbury,

Conn., a corporation of Connecticut Filed Jan. 14, 1965, Ser. No. 425,460 6 Claims. (Cl. 73-6) ABSTRACT OF THE DISCLOSURE In horology, the hairspring attached to a balance wheel should be cut to its approximate correct length. A known machine plays out the hairspring until the frequency of the hairspring and its balance wheel matches a standard frequency. The machine has an indicator disc which ceases to revolve if the two frequencies match. The present device times the stoppage of the indicator disc and cuts the hairspring if the discs is still for the predetermined time period.

The invention relates in general to machines for calibrating the regulating devices in timepieces, and more particularly to apparatus for automatically cutting to the correct length the hairsprings of the regulating devices after calibration.

In the manufacture of timepieces it is customary to manufacture the regulating device (a balance wheel and hairspring assembly) to such standards that it will operate at approximately the correct rate when it is installed in the watch. Final adjustments should be within the capability of the timepiece mechanism itself. When a balance wheel and a hairspring are assembled, the frequency of oscillation is unknown. Balance wheels vary in size and weight, and hairsprings are intentionally made longer than will be needed in the assembled timepiece. To compensate for these variables, the length of the hairspring may be adjusted until the assembly oscillates at the correct rate, It is desirable to make this adjustment before installing the regulating device in a timepiece.

In the present art are machines which automatically adjust the effective hairspring length until the frequency of the regulating device coincides with a standard frequency. In all existing machines, when the calibration is completed, the operator manually cuts off the excess hairspring length. For example, in one type of commercially available machine, the machine generates an oscillatory voltage at the frequency of oscillation of the hairspring assembly. The frequency difference between this signal and a standard frequency signal is used to control the effective length of the hairspring. The free end of the hairspring is held between wheels which vary its effective length until the correct frequency is attained. An indicator disc revolves clockwise or counterclockwise to indicate that the effective length of the hairspring is being lengthened or shortened respectively. When the operator observes that the indicator disc is stationary, he depresses a cutter lever to sever the excess hairspring length. One type of manually operated cutter using an indicator disk is manufactured by Greiner Electronic, Langenthal, Switzerland, and is described in their publication Super Spiromat-ic. The disk is shown at Figure 2, No. 20,

. in that publication.

invention also permits improved quality control over the product and makes operation of the machine a simpler task.

Other objectives and a fuller understanding of the invention may be had by referring to the following description as a preferred embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 shows a block diagram of the circuit showing wave-forms at different stages of the circuit;

FIGURE 2 shows a construction of a. photo-sensor and an indicating disc;

FIGURES 3 and 4 show angular velocities of the indicator disc as functions of time as a regulating device is calibrated;

FIGURE 5 shows one form of timer circuit; and

FIGURE 6 shows one form of time trigger circuit.

In one application of the invention, automatic cutting of the spring is achieved as follows: the photoelectric cell 1, as shown in FIG. 2, is on the opposite side from the light source 2, of a transparent disc 3 on the surface of which'disc an alternately opaque and transparent pattern is printed, Alternatively, the photoelectric cell could be placed on the same side as the light source to detect reflections off alternately light and dark areas on an opaque disc. If there is motion of the disc, a pulse output will be generated by the photoelectric device. Any other means which will convert motion of the indicator into a varying electrical output will serve, such as a cam switch or commutator. Cell 1, with its associated circuitry, is the sensor 12 of the circuit diagram of FIG. 1.

The pulse signal from sensor 12 is amplified in a pulse amplifier 4, if it is at a low level. See Millman and Taub, Pulse and Digital Circuits, New York, 1956, Chapter 3, for appropriate circuitry.

The pulse amplifier output controls the timer control 5. Timer control 5 is any circuit which will generate a direct current output voltage, increasing linearly with time, when the input is a constant value positive voltage; and which generates no output voltage when the input voltage is zero. A suitable type of circuit is shown in FIG. 5. This circuit essentially uses the input voltage to control transistor 13 as a switch which in turn controls whether or not voltage is allowed to build up across capacitor 14.

When transistor 13 is saturated, the output voltage is zero. When it is not saturated, the voltage across capacitor 14 increases roughly linearly with time if the value of capacitor 14 is large enough. i

The output of the time circuit controls the time trigger circuit 6. The time trigger circuit is any circuit which will generate an instantaneous pulse when the input voltage attains a known level, and generates zero output at all other times. A suitable circuit is shown in FIG. 6. When the input voltage reaches the trigger level of transistor 15, the transistor will fire and a voltage pulse will appear across resistance 16. Therefore, when the output voltage of the timer control circuit reaches a certain known level, indicating that the output of the timer control circuit has r not been re-set to zero for a known length of time, the

time-trigger circuit generates a pulse which causes the cutting circuit 7 to fire or go into a conductive state.

The cutting circuit is preferably a silicon-controlled rectifier circuit. It may also be a glas thyratron circuit, or any other kind of circuit which is triggered from *a non-conductive state into a conductive state by a control pulse, and which returns to a non-conductive state when the plate circuit is interrupted.

The cutting device consists of a solenoid attached to the movable cutter portion of a shear. The cutting device may, however, be any kind of a device converting an electrical energy into mechanical motion, or thereby controlling mechanical motion. For example, the energy could be used to engage a clutch on a rotary cutting device.

The monitor circuit 8 interrupts the operation of the cutter whenever a hairspring balance wheel assembly is 3 not properly positioned on the machine, and oscillating. This prevents cutting a hairspring that has stopped oscillating or has been pulled out of position.

Monitor circuit 8 is a rectifier controlling an electromagnetic relay. The input to this circuit is the alternating voltage, appropriately amplified, which is generated in the regulating machine at the frequency of the balance wheel oscillations. As long as an oscillatory input is received, the rectified output voltage energizes the relay to permit the entire circuit to operate normally. If the input is interrupted, the rectifier output will fall below the level required to energize the relay. The relay will open and interrupt further operation of the principal circuit. Monit-or circuit 8 is preferably connected to the timer control as shown, but it can also be connected into the circuit at anyplace where its effect is to interrupt operation of the hairspring cutter 19.

, The cutting circuit embodies a re-set switch 9. This switch is opened each time a calibrated hairspring assembly is removed from the machine and is closed when an uncalibrated assembly is installed. Its purpose is temporarily to break the plate circuit of the cutting circuit (assuming a gas thyratron or a silicon controlled rectifier is used) which returns the circuit to a non-conductive state. The switch preferably is a micro-switch which is automatically tripped when a calibrated hairspring assembly is removed.

If cell 1 is a single photoelectric cell, no signal will be received if the indicator comes to rest with an opaque area adjacent to the photoelectric cell, and the hairspring will not be cut. If a pattern of equally spaced light and dark areas is used, two properly located photoelectric cells theoretically will correct this defect. However, experience has shown that the optimum embodiment is three photoelectric cells.

If the width of the light and dark areas is equal and the distance between each photocell is two-thirds and the width of one light or dark area, wherever the indicator may come, to rest at least one photoelectric cell will detect a light signal so that after the correct interval, the hairspring will be cut. With each photoelectric cell is used a separate amplifier 4, timer control 5, and time-trigger circuit 6, and the output of each goes through a gate cirouit to the cutting circuit 7.

The above described embodiment of the invention operates in the following manner:

When a balance and hairspring assembly is installed in the calibrating machine and is being physically vibrated by oscillator 20 and its effective length adjusted by length adjuster 21 and is being timed, the indicator disc 3, which is the indicator 22 attached to the length adjuster 21, rotates either clockwise or counterclockwise (depending on the vibrating frequency of the balance wheel) until the balance and hairspring assembly begins vibrating at 18,000 oscillations per hour, at which time the movement I of the disc 3 stops. When the photo-sensor 1 informs the electronic unit the disc 3 has stopped rotating, the electronic timer 5 begins measuring time from to 1 seconds.

The value t is variable from 3.5 to 8 seconds. If the balance and hairspring assembly continues to vibrate at 18,- 000 oscillations per'hour during the complete time interval, the electronic unit will automatically out the hairspring. However, if the frequency of the balance and hairspring assembly drifts off the 18,000 oscillations per hour either plus or minus (i) before the end of the time period t, the calibrating machine will detect this shift in frequency of the balance assembly and automatically reset the electronic timer to zero, and will not begin measuring time until the balance assembly again is vibrating at 18,000 oscillations per hour.

By studying a typical timing curve of a hairspring and balance assembly (FIGURE 4) and by using hypothetical values, we note that the hairspring and balance assembly begins vibrating at 18,000 oscillations per hour at i At t the indicator disc has stopped rotating. The photosensor informs the electronic timer 5 to begin measuring time from to t The hairspring and balance assembly continues to vibrate at 18,000 oscillations per hour through the time interval T; therefore, three seconds after t the electronic unit automatically cuts the hairspring. The total time necessary to vibrate and cut the hairspring is thirteen seconds (T T =13 sec.)

Looking at the curve of a second hairspring and balance assembly (FIGURE 4) we see that the hairspring and balance assembly begins vibrating at 18,000 oscillations per hour at t Also at t the indicator disc 3 stops and the photo-sensor tells the electronic timer 5 to begin measuring time from t to 2 However at t the frequency of the hairspring increases a small amount causing the indicator disc 3 to move in the counterclockwise direction, correcting the length of the hairspring. The movement of the indicator-disc 3 occurs before the time measurement reaches t The photo-sensor sees the movement of the indicator-disc 3 and re-sets the electronic timer 5 to zero.

At time t; the hairspring and balance assembly again vibrates at 18,000 oscillations per hour and the electronic unit begins measuring time from L, to t (t t =T=*3 seconds). The hairspring and balance assembly continues to vibrate at 18,000 oscillations per hour throughout the time interval T; therefore, three seconds after 2 the electronic unit automatically cuts the hairspring. The total time necessary to vibrate and cut the hairspring was eighteen seconds.

Although the present invention has been described in detail, the present disclosure has been made only by Way of example and numerous changes in the details of construction and the construction and arrangement of parts may be resorted to without departing from the inventio as herein claimed.

I claim:

1. A device for calibrating a hairspring-balance wheel assembly for a timepiece, including (a) means to oscillate the hairspring-balance wheel assembly,

(b) means to adjust the effective length of the hairspring so that the said assembly oscillates at a predetermined frequency,

(c) responsive means electrically responsive to motion of the said adjusting means,

((1) timing means started by the said responsive means to measure electrically the time interval during whic the said adjusting means is stationary,

(e) means to re-start the timing means at zero if the adjusting means moves,

(f) a hairspring cutter, and

(g) means to operate the hairspring cutter when sai time interval equals a pre-determined value.'

2. The combination described in claim 1, wherein the hairspring cutting means includes a solenoid.

3. The combination described in claim 1, with additional means for permitting operation of the hairspring cutter only when a hairspring-balance wheel assembly is properly positioned and oscillating.

4. A device for calibrating a hairspring balancewheel assembly for a timepiece, including (a) means to oscillate the hairspring-balance wheel assembly,

(b) means for adjusting the effective length of the hairspring to oscillate at a predetermined frequency,

(0) an indicator attached to the said adjusting means and having a spatial arrangement of areas of contrasting light response,

(d) a light source contiguous to the said indicator,

(e) a photoelectric cell responsive to the light source as affected by the said spatial arrangement of areas of contrasting light response and contiguous to the indicator,

(f) a timer started by the photoelectric cell to measure, electrically the time interval during which a constant response is detected by the photoelectric 6. The combination described in claim 4, wherein the means and which is re-set to zero by movement of hairspring cutting means includes a solenoid. the said adjusting means, and

(g) means electrically to operate the hairspring cut- References Cited ter when said time interval equals a pre-determined 5 UNITED STATES PATENTS 2,707,875 5/1955 Hetzel 73-6 5. The combination described in claim 4, with additional means for permitting operation of the hairspring cutter only When a hairspring-balance Wheel assembly is LOUIS PRINCE Primary Exammel properly positioned and oscillating. 10 S. C. SWISHER, Assistant Examiner. 

1. A DEVICE FOR CALIBRATING A HAIRSPRING-BALANCE WHEEL ASSEMBLY FOR A TIMEPIECE, INCLUDING (A) MEANS TO OSCILLATE THE HAIRSPRING-BALANCE WHEEL ASSEMBLY, (B) MEANS TO ADJUST THE EFFECTIVE LENGTH OF THE HAIRSPRING SO THAT THE SAID ASSEMBLY OSCILLATES AT A PREDETERMINED FREQUENCY, (C) RESPONSIVE MEANS ELECTRICALLY RESPONSIVE TO MOTION OF THE SAID ADJUSTING MEANS, (D) TIMING MEANS STARTED BY THE SAID RESPONSIVE MEANS TO MEASURE ELECTRICALLY THE TIME INTERVAL DURING WHICH THE SAID ADJUSTING MEANS IS STATIONARY, (E) MEANS TO RE-START THE TIMING MEANS AT ZERO IF THE ADJUSTING MEANS MOVES, (F) A HAIRSPRING CUTTER, AND (G) MEANS TO OPERATE THE HAIRSPRING CUTTER WHEN SAID TIME INTERVAL EQUALS A PRE-DETERMINED VALUE. 